Guides
Plain-English, source-cited guides behind our apps — and the gear worth buying.
Buying guides
The best at-home water test kits (2026)Pool, spa, well, tap, and aquarium — the right kit by use case, plus strips vs liquid vs lab.
Best candle making supplies for beginners (2026)Wax, wicks, fragrance, dye, and starter kits — what to buy first.
Best food dehydrators (2026)Jerky and fruit picks, box vs stackable, and the accessory that matters for safety.
Best sous vide machines (2026)Immersion circulators and accessories by budget and batch size.
Best pressure canners & canning gear (2026)All American, Presto, jars and tools — weighted vs dial gauge.
Best soap making supplies & starter kits (2026)Lye, oils, molds, and the tools a first cold-process batch needs.
Best hydroponic nutrients & meters (2026)Flora trio vs MasterBlend, plus the EC and pH meters to dose by.
Best leatherworking tools for beginners (2026)Thread, irons, edge tools — the no-hype starter kit, and what to skip at first.
Best hard cider making equipment (2026)Fermenter, yeast, sanitizer, and bottling — what a first batch actually needs.
Best mushroom growing supplies & kits (2026)Grow kits, substrate, grain spawn, and the lab gear for going beyond kits.
Best knife making supplies (2026)The grinder, the heat-treat gear that controls hardness, and handle and sheath materials.
Best fermentation supplies (2026)Crocks, airlock lids, weights, and kombucha kits.
Best home brewing equipment (2026)Fermenters, kettles, and starter kits.
Best compost bins & tumblers (2026)Tumblers, bins, and worm farms.
Best rain barrels & diverters (2026)Barrels, diverters, and first-flush kits.
By topic
Chlorine vs. hydrogen peroxide: the dosing mathPick a sanitizer, the per-fill dosing numbers, and the one mix you must never make.
How often should you change cold plunge water?A cadence chart by tub type and sanitizer, plus when to clean the filter.
Hot tub water balance cheat sheetIdeal levels for chlorine, bromine, pH, alkalinity, and hardness — and the order to adjust them.
How much chlorine (or bromine) to addThe per-gallon dosing math, after-soak top-ups, and weekly shock, with a worked example.
Why dose magnesium before calcium and alkalinityIf Ca and Alk won’t hold, low Mg is usually why — the chemistry, dosing order, and targets.
Reef tank target parameters by tank typeCa, Alk, Mg, pH, nitrate, phosphate, and salinity targets for SPS, mixed, and LPS/soft tanks.
How much yeast for cold-ferment pizza dough?A baker’s-percentage chart for 24/48/72-hour cold ferments, plus yeast conversions.
Pizza dough hydration by styleHydration, salt, oil, and ball weight for Neapolitan, NY, Detroit, Sicilian, and Roman.
EI vs. PPS-Pro vs. PMDD: which dosing method?The three planted-tank fertilizer methods compared — schedule, water changes, and who each suits.
The PPS-Pro recipe and dosing scheduleThe exact two-bottle macro/micro mix and the daily dosing rate.
UMF glaze chemistry explainedWhat the Unity Molecular Formula tells you — oxide groups, unity, and the silica:alumina ratio.
Is your glaze food-safe? Limit formulas and leachingLimit ranges, why low silica leaches, the crazing link, and the toxic oxides to watch.
ppm, EC, and the PPM scales explainedEC vs ppm, the 500/700 scales, the 0.7 factor, and why two meters disagree.
Hydroponic nutrient targets by crop and stageEC and nutrient targets for lettuce, herbs, tomato, cucumber, strawberry — by growth stage.
Water bath vs. pressure canning: which one your food needsThe dividing line is acidity (pH 4.6). Per USDA/NCHFP, which foods need which method — and why.
Canning at altitude: how to adjust time and pressureWhy altitude changes home canning, and the USDA adjustments for water-bath time and canner PSI.
Koi pond water parameters: the levels that matterTargets and danger thresholds for pH, ammonia, nitrite, nitrate, KH, and salt.
Why your koi pond pH crashes — and the KH fixWhy low KH causes overnight pH crashes, and the baking-soda dose that fixes it.
Lye calculator basics: how to calculate NaOHSaponification (SAP) values, why every oil needs a different amount of lye, and how superfat changes the number.
Superfat and water in cold-process soap, explainedWhat superfat and water amount actually do — the three ways to express water, and how each affects your bar.
The longevity blood panel: which markers and whyApoB, Lp(a), hsCRP, HbA1c and the rest — what each measures, and the published targets named authors cite.
Optimal vs. reference ranges in bloodworkWhy your lab’s "normal" reference range describes the population, not your longevity target.
Blending cider apples: sugar, acid, and tanninThe three levers of a cider blend, the Long Ashton apple classes, and target acidity for a balanced cider.
YAN and yeast nutrient: preventing H₂S in ciderWhy apple juice is low in nitrogen, how deficiency causes H₂S and stuck ferments, and how to dose nutrient.
Why jerky must reach 160°F (165°F for poultry)Why drying alone doesn’t make jerky safe, the USDA kill-step temperatures, and when to heat.
Curing salt for jerky: how much Prague Powder #1?What Prague Powder #1 is, the standard nitrite use rate, and how curing fits the heat step.
Biological efficiency (BE): how to measure mushroom yieldWhat BE means, the formula, typical figures by species, and why dry substrate weight is the denominator.
Substrate hydration and field capacityThe squeeze test, target moisture by substrate, and why over-wet substrate invites contamination.
What salt level does a salt cell need?Target salt ppm by brand (Hayward, Pentair, Jandy), why too-low and too-high both hurt the cell.
CSI and salt cell longevityWhat the saturation index is, why a balanced index protects your cell and plaster, and the levers that move it.
Free chlorine and CYA: the ratio that keeps a pool clearWhy stabilizer changes how much chlorine you need, the FC/CYA target ratio, and why a fixed target fails.
How much chlorine or shock to add to a poolDosing liquid chlorine or cal-hypo by volume and target FC rise, routine vs. shocking, and clearing algae.
How many solar panels do I need?Size an array from daily watt-hour load, peak sun hours, and system losses — with a worked van/RV example.
What size battery bank for off-grid?Size a bank from daily load, days of autonomy, and usable depth of discharge — and why LiFePO4 and AGM differ.
Sizing a well pump: total dynamic head (TDH)What TDH is, the four components — drawdown, lift, pressure, friction — and how TDH and flow pick a pump.
UV water disinfection dose (NSF/ANSI 55)How UV dose works, the Class A 40 mJ/cm² standard, and why flow rate and clarity decide the real dose.
Quench and temper: hitting a target hardness (HRC)The austenitize–quench–temper sequence, and how each step sets the final HRC by steel.
Tempering temperature and oxide color chartWhat tempering does, the temper-color chart for plain carbon steel, and why a thermostatic oven beats colors.
Stitches per inch (SPI) by leather weightMatching SPI to leather weight and project, the SPI-to-millimeter conversion, and why proportion matters.
How much thread for a saddle stitch?A rule of thumb for cutting thread, why thickness and SPI change the multiplier, and how to avoid running short.
How to calculate red light therapy dose (J/cm²)Irradiance times time, why distance changes everything, and how to compare panels on real numbers.
Why more red light isn’t better: the biphasic dose responseToo little does nothing, an optimal window helps, too much inhibits — and what it means for sessions.
